Current signal generation is a known technique in which a signal is communicated upon a wire from a source electronic circuit to a destination electronic circuit as an output current signal rather than as an output voltage signal.
In a so-called three-wire arrangement, the current signal is carried from the source electronic circuit to the destination electronic circuit on a first wire, a power supply voltage is carried from the destination electronic circuit to the source electronic circuit on a second wire to power the source electronic circuit, and a reference potential, for example, ground, is provided on a third wire between the source electronic circuit and the destination electronic circuit.
In a so-called two-wire arrangement, the current signal is carried from the source electronic circuit to the destination electronic circuit on a first wire, a power supply voltage is carried from the destination electronic circuit to the source electronic circuit on the same first wire to power the source electronic circuit, and a reference potential, for example, ground, is provided on a second wire between the source electronic circuit and the destination electronic circuit.
The two-wire arrangement may have particular problems due to a desire to filter noise that may occur on the one wire that carries both the current signal and the power supply voltage. The filtering can be performed by a discrete capacitor coupled between the one wire and the ground wire of the two-wire arrangement. The capacitor may result in a low slew rate, i.e., slow transitions, of values of the output current signal carried by the one wire. In addition to the discrete capacitor, there may be a capacitance between the two wires of the two wire arrangement, and/or an inductance in series with one of or both of the two wires, which results in a similar low slew rate.
The three-wire arrangement may also have similar problems. While the power supply voltage can be filtered with a discrete capacitor that is not directly coupled to the wire that carries the current signal, nevertheless, the above-described capacitance between wires of the three wire arrangement, and/or the inductance in series with the wires of the three wire arrangement can result in a low slew rate of the current signal.
It would be desirable to provide a source electronic circuit operable to generate an output current signal carried from the source electronic circuit to a destination electronic circuit in a two wire or in a three wire arrangement for which a slew rate of output current signal transitions is improved.